Sentences with phrase «by hydrothermal»

Unfortunately, conductive heat flow versus age data do not confirm the cooling models because much of the heat is advected by hydrothermal circulation near the ridge axes (Hofmeister and Criss, 2005; Pollack et al., 1993).

«We didn't expect that our study of clathrates in the Enceladus ocean would lead us to the idea that methane is actively being produced by hydrothermal processes,» said lead author Alexis Bouquet, a graduate student at the University of Texas at San Antonio.

Scientists believe the ocean exists as the result of heat generated by hydrothermal activity the moon's interior.

That means it must be continuously produced there, probably by hydrothermal reactions similar to those that occur near hot vents at the bottom of Earth's oceans (Science, doi.org/b5s9).

Since then, many other possible crucibles have been identified: deep underground, in the open ocean, by hydrothermal vents on the ocean floor, on a radioactive beach and on the surface of a lump of clay.

Marbles in metamorphic aureoles and iron - rich skarns appear to be favored sites for gold mineralization in these deposits, perhaps due to the rheological character, permeability after fracturing, and chemical reactivity of those rocks to alteration by hydrothermal fluids.

More amazingly, we now know that beneath the crust of Enceladus is a global ocean of liquid saltwater and organic molecules, all being heated by hydrothermal vents on the seafloor.

Not exact matches

Further calculations by Catling and his team conclude that no abiotic methane sources on a rocky planet could produce enough of the gas to counteract this process — whether it is volcanic outgassing from a planet's interior, chemical reactions in hydrothermal vents, even asteroid impacts.

One site at Columbia Hills in Gusev crater, was visited previously by the Spirit rover and features silica deposits interpreted by some as analogous to hydrothermal springs known to be inhabited on Earth.

The hydrothermal vent system was discovered by researchers from the Centre for Geobiology at University of Bergen (Norway).

Other researchers, however, say that the fossil stromatolites were not formed by living organisms, but by physical and chemical processes around hydrothermal vents.

«We try to use continuous ground shaking produced by humans, cars, wind, water and Yellowstone's hydrothermal boilings and convert it into our signal,» Lin says.

Surrounded by treacherous fields of sharp volcanic rocks, the violent hydrothermal vents of Endeavor Ridge are an inhospitable place to lay cable, says Juniper.

This is a pastel painting of a new species, Xenoturbella profunda, found by researchers in a hydrothermal vent in the Gulf of California.

Their abundant presence on this peak may be tied to the liquid carbon dioxide spewed by the volcano's hydrothermal vents, which kills virtually all life in the deeper reaches of the crater.

Geysers and deep - sea vents are hydrothermal phenomena in which water, heated and pressurized by molten rock, is released through vents at the land surface or into the oceans.

Hydrothermal vents form by an analogous method: Ion - rich hot water is expelled from the seafloor and then begins to dissolve, forming a porous shell of metal extending upward.

This is partially because oxygen, which causes the iron to precipitate, had not yet entered the ocean to great depths, and also because the seafloor at that time contained abundant iron released by bursts of hydrothermal activity.

Heat from the friction of rocks caused by tidal forces could be the «engine» for the hydrothermal activity on Saturn's moon Enceladus.

The models reveal a «hydrothermal siphon» driven by heat loss from deep in the Earth and the flow of cold seawater down into the crust and of warmed water up out of the crust.

Gravest doubts emerged in 2002, when a team led by Oxford's Professor Martin Brasier (co-author of this current study) revealed that the host rock was not part of a simple sedimentary unit but rather came from a complex, high - temperature hydrothermal vein, with evidence for multiple episodes of subsurface fluid flow over a long time.

His team advanced an alternative hypothesis, stating that these curious structures were not true microfossils but pseudofossils formed by the redistribution of carbon around mineral grains during these hydrothermal events.

He found them in sediment collected from a hydrothermal vent, sent to him by a retired oceanographer.

In strip - mining a bit less than 30 acres of seafloor, Nautilus will consume hydrothermal chimneys and wipe out the clusters of snails and barnacles, crab and shrimp that are nourished by their sulfide emanations.

The paper, «Coupling Hydrothermal Liquefaction and Anaerobic Digestion for Energy Valorization From Model Biomass Feedstocks,» was co-authored by Rodrigo A. Labatut, Pontifical Catholic University of Chile; Andrew H. Kim; and former post-doctoral researcher Joseph G. Usack.

Three new papers co-authored by Mike Russell, a research scientist at NASA's Jet Propulsion Laboratory, Pasadena, Calif., strengthen the case that Earth's first life began at alkaline hydrothermal vents at the bottom of oceans.

The researchers show that by using hydrothermal liquefaction before anaerobic digestion, virtually all of the energy is extracted from the food waste.

Deep - sea organisms including mussels thrive in the extreme environments of hydrothermal vents and cold seeps which are characterised by high hydrostatic pressure, lack of photosynthesis - derived food, variable temperatures and high concentrations of toxic substances.

However, the hydrothermal theory is contradicted by geological evidence that the gold concentration must have taken place during the formation of host sediments on the Earth's surface.

These fields are surrounded by a unique set of animals, including vent crabs and eyeless vent shrimp, that survive off of the chemicals emitted from the hydrothermal vents.

Grassle's work ultimately revealed that a diverse community of organisms thrives along deep - sea hydrothermal vents, feasting on organic matter produced by sulfur - oxidizing bacteria instead of photosynthesis.

In the deep gold mines of South Africa, and under the sea, at hydrothermal vents where breaks in the fissure of Earth's surface that release geothermally heated waters — hydrogen - rich fluids host complex microbial communities that are nurtured by the chemicals dissolved in the fluids.

The remarkable density of life at deep - sea hydrothermal vents is explained by the mutually beneficial symbiosis of invertebrate animals and sulfide - oxidizing bacteria that colonize their cells

Transport by these deep - reaching eddies provides a mechanism for spreading the hydrothermal chemical and heat flux into the deep - ocean interior and for dispersing propagules hundreds of kilometers between isolated and ephemeral communities.

* David Kring explores the hydrothermal system triggered by the impact, including metasomatism (lithologic chemistry altered by hot fluids), and how the system could have incubated new life as it cooled over thousands of years post-impact.

The group is represented by possible habitat generalists (such as the large Enteroctopus dofleini which ranges from the intertidal to depths in excess of 450 m) and specialists (such as Vulcanoctopus hydrothermalis which is found only in hydrothermal vents).

Hydrothermal vents, known as black smokers, were first discovered on Earth in 1977 on the Galápagos Rift [see «The Crest of the East Pacific Rise,» by Ken C. Macdonald and Bruce P. Luyendyk; Scientific American, May 1981].

Images retrieved by NASA's Cassini spacecraft from one of Saturn's moons, Enceladus, show that hydrothermal vents may not be unique to our home planet.

Its purpose is to display and interpret original works by a science illustrator who, in collaboration with a scientist, has visited and documented hydrothermal vent ecosystems via travel in the deep - sea submersible Alvin.

If hydrothermal chemical reactions are indeed responsible for the molecular hydrogen, that means the methane previously detected by Cassini might be generated from carbon dioxide (also detected by Cassini) through a reaction with hydrogen.

Subsequent explorations by the deep - sea submersible Alvin revealed not only the presence of hydrothermal vents, but also a startling array of giant worms, clams, and mussels.

Of course, the formation and evolution of a hydrothermal vent system is complicated by the fact that nothing is ever «permanent» on the sea floor.

The authors agree both scenarios are likely occurring to some degree, but they note that the presence of nanosilica grains, as documented by the other paper, favors the hydrothermal scenario.

«To explain these features, we suggest that abyssal hill hydrothermal venting occurs in frequent bursts, possibly triggered by earthquakes,» said Haymon.

The Grand Prismatic hot spring is among the national parks myriad hydrothermal features created by the Yellowstone supervolcano.

It is also the main component of naturally occurring hydrocarbon gas reservoirs, and a contribution is also provided by volcanic and hydrothermal activity.

AB: Since many astrobiologists are currently examining hydrothermal vents, in search of extremophiles, does the prebiotic chemistry actually get decomposed rather than enhanced by the presence of such ocean venting?

Scientists are especially interested in measuring the amount of hydrogen gas in the plume, which would tell them how much energy and heat are being generated by chemical reactions in hydrothermal vents at the bottom of the moon's ocean.

Additional unprocessed images gathered during Cassini's plunge are available online, along with hundreds of thousands collected by the probe during the more than 13 years it has spend studying Saturn and its moons — observations which resulted in the publication of more than 3,000 studies and such discoveries as liquid methane seas at Titan and hydrothermal activity on Enceladus.

Using infrared data collected at Mars by spacecraft, they can interpret which minerals are there and describe the geology of ancient hydrothermal systems.